3 ms·

> I'd love an implementation of a Lisp with a Hindley Milner-esque type system. I am not certain of whether it is more Hindley-Milner or more "esque", but you

by jpt4 10y ago

> I'd love an implementation of a Lisp with a Hindley Milner-esque type system. I am not certain of whether it is more Hindley-Milner or more "esque", but you may find something of interest in Shen [0]. [0] http://shenlanguage.org/ http://shenlanguage.org/ Edit: I submitted this reply an hour or so after opening the tab, during which interval several others mentioned Shen (which is good, as it deserves a bit of exposure).

emidln 10y ago
Shen (in particular its type system) is an executable Sequent Calculus system [0] written with a small portable lisp. This derives from a propositional logic system, not H-M over typed lambda calculus. [0] - http://www.shenlanguage.org/learn-shen/types/types_sequent_calculus.html http://www.shenlanguage.org/learn-shen/types/types_sequent_c...
- jpt4 10y ago
  Thank you for clarifying. Can you comment on the relative expressive power of Shen's type system versus e.g. Haskell? I understand that the former can accept as well-typed terms the other can't; in what way is this a consequence of modeling Shen's type system using the Sequent Calculus versus Hindley-Milner deduction?
eschaton 10y ago
The page describing Shen uses the terms "proprietary" and "closed source" as if they're good things when describing the "Shen Professional" dialect. (Compiler? Environment? It's a bit opaque.) I'm certainly no Free Software zealot, but that's been an almost unfailing recipe for getting a language and its ideas ignored for 20+ years now.
- sklogic 10y ago
  Shen was opensourced some time ago, under a BSD-style license: https://github.com/Shen-Language/shen-sources/blob/master/BSD https://github.com/Shen-Language/shen-sources/blob/master/BS...
  - eschaton 10y ago
    And the creators appear to be reserving some features for the "commercial" version, and also attempting to heavily promote that version in a way which—I think, based on a few decades' experience—will actively turn away the people who might otherwise be interested in using it.

by jpt4 10y ago

emidln 10y ago

Shen (in particular its type system) is an executable Sequent Calculus system [0] written with a small portable lisp. This derives from a propositional logic system, not H-M over typed lambda calculus. [0] - http://www.shenlanguage.org/learn-shen/types/types_sequent_calculus.html http://www.shenlanguage.org/learn-shen/types/types_sequent_c...

jpt4 10y ago
Thank you for clarifying. Can you comment on the relative expressive power of Shen's type system versus e.g. Haskell? I understand that the former can accept as well-typed terms the other can't; in what way is this a consequence of modeling Shen's type system using the Sequent Calculus versus Hindley-Milner deduction?

eschaton 10y ago

The page describing Shen uses the terms "proprietary" and "closed source" as if they're good things when describing the "Shen Professional" dialect. (Compiler? Environment? It's a bit opaque.) I'm certainly no Free Software zealot, but that's been an almost unfailing recipe for getting a language and its ideas ignored for 20+ years now.

sklogic 10y ago
Shen was opensourced some time ago, under a BSD-style license: https://github.com/Shen-Language/shen-sources/blob/master/BSD https://github.com/Shen-Language/shen-sources/blob/master/BS...
- eschaton 10y ago
  And the creators appear to be reserving some features for the "commercial" version, and also attempting to heavily promote that version in a way which—I think, based on a few decades' experience—will actively turn away the people who might otherwise be interested in using it.